In an Orthogonal Frequency Division Multiplexing (OFDM) communication system, uplink/downlink data packets are transmitted in units of subframes, each of which is defined as a specific time interval including multiple OFDM symbols. In the system, multiple terminals can communicate through one base station and wireless resources are allocated through scheduling of the respective terminals. Uplink/downlink communication of a terminal is performed through the resources allocated in subframes.
Here, not only uplink/downlink data packets but also various pieces of control information for transmission of the uplink/downlink data packets are transmitted. The control information includes various pieces of information required to transmit and receive uplink/downlink data packets such as wireless resource information, coding methods, and modulation methods used for transmitting and receiving uplink/downlink data packets. Resources are allocated to all or part of multiple OFDM symbols included in one subframe for transmitting such various pieces of control information as well as for transmitting data packets. The control information is transmitted through the allocated resources in the subframe.
According to wireless resource scheduling for transmitting uplink/downlink data packets and control information of multiple terminals, the base station maps corresponding information bits to wireless resources to transmit the information bits to the terminals. In the case of downlink control channel transmission, mapping wireless resources to control channels for terminals so that the control channels are uniformly distributed and transmitted over the allocated wireless resources advantageously achieves diversity effects since pieces of control information of a number of terminals can be transmitted together in downlink. In the case where scheduling is performed using virtual resource units, a method for mapping the virtual resource units to actual physical resources should be provided to perform actual transmission.